System and Method for Supporting Inter-Band Carrier Aggregation with Different UL/DL TDD Configurations

1. A method of wireless communications between a wireless communications network and wireless user equipment, comprising: receiving, using a primary time division duplex (TDD) configuration, data on a primary component carrier in a first frequency band; receiving, using a secondary TDD configuration, data on a secondary component carrier, in a first subframe, in a secondary frequency band different from the first frequency band, wherein the secondary TDD configuration defines a second subframe, relative to the first subframe, for transmitting a Hybrid Automatic Repeat Request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) for the data received on the secondary component carrier; determining that the HARQ ACK/NACK for the data received on the secondary component carrier is to be transmitted on the primary component carrier; and in response to the determining, transmitting, using the primary component carrier, the HARQ ACK/NACK for the data received on the second component carrier using a supplemental TDD configuration, wherein the HARQ ACK/NACK is transmitted in a subframe different from the second subframe and the supplemental TDD configuration comprises a supplemental downlink TDD configuration, the supplemental downlink TDD configuration specifying a set of downlink subframes including downlink subframes specified in the primary TDD configuration and the secondary TDD configuration.

2. The method of claim 1 , wherein the primary TDD configuration comprises a primary downlink TDD configuration including downlink subframes, and the secondary TDD configuration comprises a secondary downlink TDD configuration including downlink subframes.

3. The method of claim 1 , further comprising transmitting a HARQ ACK/NACK for data received on the secondary component carrier, using a supplemental TDD configuration, wherein the supplemental TDD configuration specifies a set of uplink subframes including uplink subframes in the primary TDD configuration and the secondary TDD configuration.

4. The method of claim 3 , further comprising receiving, using the supplemental TDD configuration, an uplink grant granting resources for uplink data transmissions on the secondary component carrier.

5. The method of claim 4 , further comprising retransmitting an uplink data packet on the secondary component carrier at a modified uplink retransmission subframe different from an uplink retransmission subframe specified by the supplemental TDD configuration.

6. The method of claim 5 , wherein the modified uplink retransmission subframe is a subframe preceding the uplink retransmission subframe.

7. The method of claim 5 , wherein the modified uplink retransmission subframe is a next available uplink subframe not previously scheduled after the uplink retransmission subframe.

8. The method of claim 1 , wherein the supplemental TDD configuration comprises a supplemental downlink TDD configuration or a supplemental uplink TDD configuration.

9. The method of claim 1 , further comprising receiving data on tertiary component carrier using a third TDD configuration in a third frequency band different from the first frequency band and the second frequency band, wherein the supplemental TDD configuration comprises an aggregations of the primary TDD configuration and third TDD configuration.

10. The method of claim 1 , further comprising in response to not receiving a DL PDCCH to schedule grants, executing at least one of Cross Transmission Time Interval (TTI) scheduling, bundle scheduling, or temporarily disable cross-carrier scheduling.

11. User Equipment for wireless communications with a wireless communications network, comprising: one or more processors configured to: receive, using a primary time division duplex (TDD) configuration, data on a primary component carrier in a first frequency band; receive, using a secondary TDD configuration, data on a secondary component carrier, in a first subframe, in a secondary frequency band different from the first frequency band, wherein the secondary TDD configuration defines a second subframe, relative to the first subframe, for transmitting a Hybrid Automatic Repeat Request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) for the data received on the secondary component carrier; determine that the HARQ ACK/NACK for the data received on the secondary component carrier is to be transmitted on the primary component carrier; and in response to the determining, transmit, using the primary component carrier, the HARQ ACK/NACK for the data received on the second component carrier using a supplemental TDD configuration, wherein the HARQ ACK/NACK is transmitted in a subframe different from the second subframe and the supplemental TDD configuration comprises a supplemental downlink TDD configuration, the supplemental downlink TDD configuration specifying a set of downlink subframes including downlink subframes specified in the primary TDD configuration and the secondary TDD configuration.

12. The user equipment of claim 11 , wherein the primary TDD configuration comprises a primary downlink TDD configuration including downlink subframes, and the secondary TDD configuration comprises a secondary downlink TDD configuration including downlink subframes.

13. The user equipment of claim 11 , the processors further operable to transmit a HARQ ACK/NACK for data received on the secondary component carrier, using a supplemental TDD configuration, wherein the supplemental TDD configuration specifies a set of uplink subframes including uplink subframes in the primary TDD configuration and the secondary TDD configuration.

14. The user equipment of claim 13 , the processors further operable to receive, using the supplemental TDD configuration, an uplink grant granting resources for uplink data transmissions on the secondary component carrier.

15. The user equipment of claim 14 , the processors further operable to retransmit an uplink data packet on the secondary component carrier at a modified uplink retransmission subframe different from an uplink retransmission subframe specified by the supplemental TDD configuration.

16. The user equipment of claim 15 , wherein the modified uplink retransmission subframe is a subframe preceding the uplink retransmission subframe.

17. The user equipment of claim 15 , wherein the modified uplink retransmission subframe is a next available uplink subframe not previously scheduled after the uplink retransmission subframe.

18. The user equipment of claim 11 , wherein the supplemental TDD configuration comprises a supplemental downlink TDD configuration or a supplemental uplink TDD configuration.

19. The user equipment of claim 11 , the processors further operable to receive data on tertiary component carrier using a third TDD configuration in a third frequency band different from the first frequency band and the second frequency band, wherein the supplemental TDD configuration comprises an aggregations of the primary TDD configuration and third TDD configuration.

20. The user equipment of claim 11 , the processors further operable to, in response to not receiving a DL PDCCH to schedule grants, execute at least one of Cross Transmission Time Interval (TTI) scheduling, bundle scheduling, or temporarily disable cross-carrier scheduling.

21. An apparatus comprising instructions embodied on a tangible, non-transitory computer-readable medium, the instructions operable when executed to cause a computing system to perform operations comprising: receiving, using a primary time division duplex (TDD) configuration, data on a primary component carrier in a first frequency band; receiving, using a secondary TDD configuration, data on a secondary component carrier, in a first subframe, in a secondary frequency band different from the first frequency band, wherein the secondary TDD configuration defines a second subframe, relative to the first subframe, for transmitting a Hybrid Automatic Repeat Request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) for the data received on the secondary component carrier; determining that the HARQ ACK/NACK for the data received on the secondary component carrier is to be transmitted on the primary component carrier; and in response to the determining, transmitting, using the primary component carrier, the HARQ ACK/NACK for the for data received on the second component carrier using a supplemental TDD configuration, wherein the HARQ ACK/NACK is transmitted in a subframe different from the second subframe and the supplemental TDD configuration comprises a supplemental downlink TDD configuration, the supplemental downlink TDD configuration specifying a set of downlink subframes including downlink subframes specified in the primary TDD configuration and the secondary TDD configuration.